Pressing arrangement for treating substances

Abstract

The present invention relates to a pressing arrangement for treatment of articles by hot pressing and in particular to a pressing arrangement for hot isostatic pressing of containers holding substances. The method comprises: placing containers including the substance in a load compartment in the furnace and loading a pressure medium into the pressure vessel and substantially all pressure medium flowing out from the furnace chamber (18) passes at least one substance capturing module, which may include the walls of the guiding passage, at least one condensation element (35) in the guiding passage, filters (41, 43) arranged in the guiding passage, before making contact with the pressure vessel including the top and bottom closures (8, 9).

The invention claimed is: 
     
       1. A pressing arrangement for hot isostatic pressing of substances, comprising:
 a pressure vessel including top and bottom end closures; 
 a furnace chamber provided inside the pressure vessel and being adapted to hold articles such as containers comprising substances to be treated by hot isostatic pressing, 
 a heat insulated casing including a heat insulating portion, a housing and a bottom heat insulating portion; 
 a guiding passage being defined by said heat insulating portion and said housing, said guiding passage communicating with the furnace chamber and being a part of an outer cooling loop, wherein said pressure medium is guided toward said top closure in said guiding passage; 
 at least one upper hole arranged substantially at the same height as said bottom heat insulating portion to allow pressure medium to flow into said guiding passage from said furnace chamber; and 
 at least one substance capturing module adapted to capture substances carried by said pressure medium, wherein said at least one substance capturing module is arranged such that all pressure medium flowing out from said furnace chamber passes said at least one substance capturing module before making contact with said pressure vessel including said top and bottom closures, wherein said at least one substance capturing module is arranged in said outer cooling loop within said housing such that the pressure medium flowing out from said furnace chamber is forced to pass said at least one substance capturing module via said guiding passage before making contact with said pressure vessel; and 
 a sealing arranged between an upper space, which is below the furnace chamber, and a lower space, which is below the bottom heat insulating portion, so as to ensure that the pressure medium flowing out from the furnace chamber is forced to pass the at least one substance capturing module via the guiding passage prior to entering the lower space. 
 
     
     
       2. The pressing arrangement according to  claim 1 , wherein said at least one substance capturing module comprises at least one condensation element arranged in said guiding passage, wherein substances carried by said pressure medium can condensate on said condensation element when passing said condensation element. 
     
     
       3. The pressing arrangement according to  claim 2 , wherein said at least one substance capturing module comprises at least one first filter arranged downstream said at least one upper hole. 
     
     
       4. The pressing arrangement according to  claim 3 , wherein said at least one first filter is arranged downstream said condensation element and arranged such that said pressure medium passes through said first filter before making contact with said pressure vessel including said top and bottom closures. 
     
     
       5. The pressing arrangement according to  claim 3  or  4 , wherein said at least one first filter is arranged in said guiding passage between said at least one upper hole and at least one opening in an upper part of said guiding passage. 
     
     
       6. The pressing arrangement according to  claim 1 , wherein at least one lower hole is arranged below said at least one upper hole in a lower part of the guiding passage. 
     
     
       7. The pressing arrangement according to  claim 6 , wherein said at least one lower hole is arranged below said sealing to allow colder pressure medium to flow into said guiding passage from a space below said bottom heat insulating portion. 
     
     
       8. The pressing arrangement according to  claim 6 , wherein said at least one substance capturing module comprises at least one second filter arranged in connection with the at least one lower hole such that substances carried by pressure medium are substantially prevented from entering said space below said bottom heat insulating portion. 
     
     
       9. The pressing arrangement according to  claim 8 , wherein said least one second filter is arranged in said guiding passage. 
     
     
       10. The pressing arrangement according to any one of  claims 3 - 4  or any one of  claims 6 - 9 , wherein said first and/or second filter is an electro-static filter or a chemically active filter. 
     
     
       11. A method for hot pressing of substances using a pressing arrangement, said pressing arrangement including a pressure vessel including top and bottom end closures, a furnace chamber provided inside the pressure vessel and being adapted to hold articles such as containers comprising substances to be treated by hot pressing, and a heat insulated casing including a heat insulating portion, a housing and a bottom heat insulating portion, wherein a guiding passage is defined by said heat insulating portion and said housing, said guiding passage communicating with the furnace chamber and being a part of an outer cooling loop, said heat insulating portion and said bottom heat insulating portion being arranged to enclose said furnace chamber, the pressing arrangement further comprising a sealing arranged between an upper space, which is below the furnace chamber, and a lower space, which is below the bottom heat insulating portion, the sealing being arranged so as to ensure that the pressure medium flowing out from the furnace chamber is forced to pass the at least one substance capturing module via the guiding passage prior to entering the lower space, said method comprising:
 placing containers including said substances in a load compartment in said furnace; 
 loading a pressure medium into said pressure vessel; 
 pressurizing said pressure vessel to a pressure between 200 to 5000 bars, and preferably 800 to 2000 bars, and more preferably 500 to 1500 bars; 
 maintaining temperature in said pressure vessel from between 300° C. to 3000° C., and preferably from 800° C. to 2000° C.; 
 conveying all pressure medium flowing out from said furnace chamber such that the pressure medium passes at least one substance capturing module via said guiding passage of the outer cooling loop within said housing before making contact with said pressure vessel including said top and bottom closures, wherein the sealing ensures that the pressure medium flowing out from the furnace chamber is forced to pass the at least one substance capturing module via the guiding passage prior to entering the lower space below the bottom heat insulating portion; 
 reducing said temperature within the pressure vessel; and 
 releasing pressure in said pressure vessel. 
 
     
     
       12. The method according to  claim 11 , further comprising conveying substantially all said pressure medium flowing out from said furnace chamber to pass at least one condensation element of said substance capturing module arranged in said guiding passage, wherein substances carried by said pressure medium can condensate on said condensation element when passing said condensation element. 
     
     
       13. The method according to  claim 11  or  12 , further comprising conveying substantially all pressure medium flowing out from said furnace chamber to pass at least one first filter arranged downstream said at least one upper hole. 
     
     
       14. The method according to  claim 11  or  12  further comprising conveying cold pressure medium through at least one lower hole arranged below the sealing to flow into said guiding passage from said lower space below said bottom heat insulating portion.